Data_Sheet_1_A Novel Promazine Derivative Shows High in vitro and in vivo Antimicrobial Activity Against Staphylococcus aureus.docx

The emergence of multidrug-resistant bacteria constitutes a significant public health issue worldwide. Consequently, there is an urgent clinical need for novel treatment solutions. It has been shown in vitro that phenothiazines can act as adjuvants to antibiotics whereby the minimum inhibitory concentration (MIC) of the antibiotic is decreased. However, phenothiazines do not perform well in vivo, most likely because they can permeate the blood-brain (BBB) barrier and cause severe side-effects to the central nervous system. Therefore, the aim of this study was to synthesize a promazine derivate that would not cross the BBB but retain its properties as antimicrobial helper compound. Surprisingly, in vitro studies showed that the novel compound, JBC 1847 exhibited highly increased antimicrobial activity against eight Gram-positive pathogens (MIC, 0.5–2 mg/L), whereas a disc diffusion assay indicated that the properties as an adjuvant were lost. JBC 1847 showed significant (P < 0.0001) activity against a Staphylococcus aureus strain compared with the vehicle, in an in vivo wound infection model. However, both in vitro and in silico analyses showed that JBC 1847 possesses strong affinity for human plasma proteins and an Ames test showed that generally, it is a non-mutagenic compound. Finally, in silico predictions suggested that the compound was not prone to pass the BBB and had a suitable permeability to the skin. In conclusion, JBC 1847 is therefore suggested to hold potential as a novel topical agent for the clinical treatment of S. aureus skin and soft tissue infections, but pharmacokinetics and pharmacodynamics need to be further investigated.

多重耐药菌的出现已构成全球范围内重大的公共卫生问题，临床亟需新型治疗方案。体外实验证实，吩噻嗪类可作为抗生素佐剂，能够降低抗生素的最低抑菌浓度（minimum inhibitory concentration, MIC）。然而，吩噻嗪类在体内实验中效果不佳，究其原因大概率是该类物质可透过血脑屏障（blood-brain barrier, BBB），对中枢神经系统造成严重不良反应。因此，本研究旨在合成一种无法透过血脑屏障、却仍保留抗菌辅助活性的丙嗪衍生物。令人意外的是，体外实验显示，新型化合物JBC 1847对8株革兰阳性病原菌展现出显著增强的抗菌活性（最低抑菌浓度为0.5~2 mg/L），但纸片扩散试验结果表明，其作为佐剂的特性已丧失。在体内伤口感染模型中，与赋形剂对照组相比，JBC 1847对金黄色葡萄球菌菌株展现出显著的抗菌活性（P < 0.0001）。不过，体外实验与计算机模拟（in silico）分析均显示，JBC 1847对人血浆蛋白具有较强的结合亲和力；艾姆斯试验（Ames test）结果表明，该化合物整体无致突变性。最后，计算机模拟预测结果显示，该化合物不易透过血脑屏障，且具备适宜的皮肤渗透性。综上，JBC 1847有望成为治疗金黄色葡萄球菌皮肤及软组织感染的新型外用制剂，但仍需进一步研究其药代动力学与药效动力学特性。